US pharmaceutical major Pfizer Inc on July 28 said that it would start an immunogenicity and safety study to evaluate the updated version of its new Covid-19 vaccine, which is targeted to fight against the Delta variant.
"We also plan to start an immunogenicity and safety study in August to evaluate an updated version of our vaccine specifically designed to target the Delta variant," Pfizer Inc said in a statement.
The pharma major also said that the highly contagious Delta variant now represents approximately 83 percent of sequenced cases in the US.
Pfizer had in the past said that it believes a third "booster" dose of its vaccine will be needed in the future. On Wednesday, the firm added that it may file for an emergency use authorisation for a potential booster dose as early as August.
Frequently Asked Questions
A vaccine works by mimicking a natural infection. A vaccine not only induces immune response to protect people from any future COVID-19 infection, but also helps quickly build herd immunity to put an end to the pandemic. Herd immunity occurs when a sufficient percentage of a population becomes immune to a disease, making the spread of disease from person to person unlikely. The good news is that SARS-CoV-2 virus has been fairly stable, which increases the viability of a vaccine.
There are broadly four types of vaccine — one, a vaccine based on the whole virus (this could be either inactivated, or an attenuated [weakened] virus vaccine); two, a non-replicating viral vector vaccine that uses a benign virus as vector that carries the antigen of SARS-CoV; three, nucleic-acid vaccines that have genetic material like DNA and RNA of antigens like spike protein given to a person, helping human cells decode genetic material and produce the vaccine; and four, protein subunit vaccine wherein the recombinant proteins of SARS-COV-2 along with an adjuvant (booster) is given as a vaccine.
Vaccine development is a long, complex process. Unlike drugs that are given to people with a diseased, vaccines are given to healthy people and also vulnerable sections such as children, pregnant women and the elderly. So rigorous tests are compulsory. History says that the fastest time it took to develop a vaccine is five years, but it usually takes double or sometimes triple that time.
"We continue to believe it is likely that a third dose booster may be needed within 6 to 12 months after full vaccination to maintain the highest levels of protection, and studies are underway to evaluate the safety and immunogenicity of a third dose," the company said.
Pfizer and BioNTech initiated a Phase 2/3 study in June 2021 to further evaluate the safety, tolerability and immunogenicity of BNT162b2 -- COVID-19 vaccine -- in preventing COVID-19 in healthy children between the ages of 6 months and 11 years.
Mentioning an update on the ongoing Phase 1/2/3 booster trial of a third dose of the current BNT162b2 vaccine, Pfizer said, "Initial safety and immunogenicity data from the study demonstrate that a booster dose given at least 6 months after the second dose has a consistent tolerability profile while eliciting high neutralization titers against the wild type and the Beta (B.1.351) variant, which are 5 to 10 times higher than after two primary doses."
"The companies expect to have the safety and immunogenicity data that could potentially support an Emergency Use Authorisation (EUA) for use in children aged 5 to 11 years old, if such an EUA is deemed necessary, by the end of September. The full dataset from this study, which will be required to support licensure in this age group, is expected by the end of 2021. Similar data packages will be submitted shortly thereafter to support EUA and licensure in children 6 months to 5 years of age," Pfizer added in its quarterly earnings update on July 28.
The pharma firm -- in its quarterly earnings update -- has raised its full-year revenue projections for its coronavirus vaccine by almost a third, following its vaccine helped it to almost double its sales in the second quarter.
Pfizer upgraded its 2021 revenue forecast for the COVID-19 vaccine shot to $33.5 billion from the $26 billion it had predicted in the previous quarter. It had generated direct sales of $7.8 billion from the vaccine in the second quarter.